Curtain stretcher



May 15, 1928.

1,669,926 C. G. CARLSON CURTAIN STRETCHER Filed Feb. 6, 1926 I 2 Sheets-Sheet 1 May 15, 1928.

C. G. CARLSON CURTAIN STRETC'HER eet 2 Filed Feb. 6, 1926 Patented May 155, 1928.

, CHARLES acanrson, F cmcneo, rumors.

con/ram. srnintrcm Application filed iebruary The present invention relates primarily to thecurtain stretcher as a whole, that to say,-tothe frame Worlg comprising the four pin rails disposed inrectangular relation to .6 one another, together with the corner clamps which serve to hold the pin rails rigidly together when the component parts of the frame are assembled.

In certain prior constructions, with which I am familiar, it is the practice tounite all four corners of ,the frame by means of clamping members of uniform character, but I. have found that better results-may be obtained by the useof clamping members of diverse character, one pair of clamps being provided to unite twoof the corners with the rails in abutting relation to one another, and another pair of clamps, of a different type, being employed tounite the remaining two corners with the pin rails in overlapping relation. This method of building .up .or assembling the constituent portions of the frame resultsin precision and accuracyof adjustment, and also provides a v framepossessing great rigidity and resistance to distortion from its true rectangular configuration, v The present invention is directed to the frame as a Whole, and also to the special form of clamp which is utilized for uniting the overlapped corners, which'clamp is of a character which tends to square up the frame as a wholewhenthe clamps\are ad justed to place, and also provides. a corner brace of peculiar characterfOr. reinforcing and stabiliaing the frame. The companion pair ofclamps, which are used tofunit'e the corners afforded by the butt ended pin rails, is also believed topossessfeatures of novelty, butthis special form of clamp per se forms the subjectof a separate" application and will be here claimed only in itscombined relation to. the frame as a whole. Further?objectsfandldetails will appear froma descr ption ofthe invention'wheremc l i Figure. 1 shows a planview ofthe frame 7 a as a whole, sections of the railsbeing' broken out. to reduce the size of the figure to appigpriate dimensions; a

i the special form of overlapped comers, showing I the pin railsin dotted lines;

"bracing clamp 1 for the the position of inwardly from longitudinal sectional view of Thecorner abutment 21 isfittedto slide 6, 1926. said No. 186,403.

Fig. 3 is a sectionof the same taken at right angles to the disclosure of Fig. 2;

Fig. 4 isan end elevation of said clamp; and i 1 ig. '5 clamp in position at opposite ends at one of the'pin rails. n y

The .frame comprises four pinrails cluding what may,

for convenience, be

is a View showing both forms of termed side rails 10 and 11, and end-rails l2 and 13. Preferably, though not necessarily, the so-called siderails are somewhat longer thanqthe end i'ails,'but obvio'usly'the dimensions of the respective rails will con- I form to the use for which the stretcher is intended.

The end rails 12 and 13 lie in spaced parallel relation, and on one side 'of the frame their ends are overlappedor crossed by the side rail 10' extendin in right angle relation to the end rails. The overlapped ends are embraced by a diagonally disposed bracing clamp let of U-shaped formation comprising parallel spacedside plates 15 and a connecting crosshead 16 through which extends an adjusting screw 17 provided with a handle 18.

Thebrace clamp as a whole is formed of a strip of sheet-metal bent to the proper shape, and the center of the head has a metal struck inwardly to, afford a boss 19 through which the adjusting screw is threaded; .In order to more perfectly reinforce'the head and stiffen it to withstand the thrust of the screw, the side edges of the crossjhead are turned inwardly to afford flanges 20 which give a channehlike formation to the head as a whole.

The inner end of the screw 17 is pointed and bears against ner'abutment 21 of right angular formation comprising bearing faces 22 and23 bent at right angle relation to one another "and also comprising triangular end walls 24: which give to the corner abutment, as awhole, the

configuration of a. hollow'half cube but through diagonally opposed edges. It is preferred to form the corner abutment from a singleplate of material withthe ends bent one of the side faces.

between the side plates clamp, which-plates,

15 of the present the inner angle of-a cor lOl near'thehead ends, are

4 ,0 in the side the abutment 38 which will abutting relation, that it is not deemed necessary to describe such that when the adjusting screw isitu-lned inwardly, it will exert a thrust against the inner angle of the abutment andforce'thei same inwardly against the-pronimatefaces of the overlapped pin'rai'lsl lhsdn dicatedin Fig. 3, the spread of the side plates 15 1s sufiicien't toeinbr'ace'the pin rails when overlapped, and the length'of "the abutment 21 is suflicient to aiford *fulhbe'aring surface against the subtended portions of the pm rails.

The adjustable abutm'entfil co operates witha fixed corner abutment Z'Zdembraced between the -opposite ends of theside plates I5 andjheld in fixed relation thereto by the plfdvision of a pair o f screws 28 flwhich act in conjunction with "tongues 29 struck out wardly from'the free edgesof the'end "walls 3010f the abutment in position to lie within companion recesses 313 l"in the and edges ofthe plates 15, the arrangement beingsuch that pivotal movement upon the screws 281s thus prevented. The general configuration df'the end abutment27is precisely similar to that of the abutment 21, theendabutment having angularly disposdWalls 32 whi'ch bear against the, proximate faces of the pin rails,"i1i opposed relation to-the contact atfordedby the adjustable abutment *21, as clearly indicated in Fig.2, from which it will appear that the co-acting abutments fit squarely within the opposing "outerangles at the overlapped corner of tl16 ;fl'111l'ei The remainingfltwo corners afforded by the 'butted pin rails, which lie in flush relation to one another, are held"ii1 assembl'ed relation by the provision of apair of loop shaped clamps 33 each comprising aside p1ates34 and'35'andfia cross head 36. .The

cross head has entered therethrough an adjusting screw 37 which bears against the interiorof "a U-shaped abutment 38, the side wallsea of whic'liare guided within'recesse's edges of the cross head 13*6,lthe t a turning up advancement of th'us exert prespinrailll. The

arrangement being such tha oi .the screw 37 "will cause sure ai'nstfthe'edge of the.

side p ates 3 and '35 are "connected to the en 9f theend r'a'ilj'13 bymea'ns of rivets 1'1 and '42, 'or in any other suitabl'e manner.

The special details of-th'e clamp 35 are not deemed to constitute a'parto'f thepresent invention, and in'so far asthe ,general combination is concerned, other types of clamps, adapted 'tohold'the parts in fiu'sh might be substituted, so

' sans with or illustrate,- such cisionthan ishere indicated.

(greater ipre- The'pin rails are themselves of the type common in curti'on shown, the

, operation; of these two ne tain stretcher construction, being recessed behindthetr inner edges, 'as'nt aefi and provided witli' the usual undereut' channels 44 within which the pins 45 mounted. V

It will be observed that in the construcloop shaped clamps 33 are permanently united to and extend outwardly are slidably from thewnelwtifthe end rails 12 and 13 while the corner brace clamps 14; are not perm'anently united "to the rails, hnt constitnte separa'ble fixtures *adapted'to besli d 'in place inidiagon'a-l relation tothe over a ed corners'whenthe iframe is being assent Fed Inord'er' to assemble the apresent frame, the clamps 33 are first loosened up sultt ciently to permit "insertion of the side wall 11 through the spaces thus aficrded, 'atter which the end rails '12'and T3 are adj usted to afiord the proper'sp'ace relation which will be'jindicated by the usual graduated scale common 'in-devices-cff this character. fifterthe'parts-have been thus fld'jlFSbCdfdihB screws "37 will be "tightened up, iforcingmhe 'U-shaped abutments38 against the proximateedge'portions of'the rail "1 1 until the parts are held in :sulficientlfy firm con-tact to preventslippin With three si esiof the frame "thus 'aesem .bledjthe railIO will ice-slipped through the "corner brmce clamps, wh-idh are l loosened up suificiently to' permit bf this adjustment, "after 'which "the thumb screws 17 will be turned down to"'force ithe adjustable abut- "ments'firml intoeontactWltilYthe proximate corners. his adjustment will have the effect of exactly squaring'nptheframe ias a whole for-the reason that-the co-acting corfner 'abutments 'ea'ch present 'their contact "faces inrightanglerelation to 'one another, so that when the "two 'abutments are "forced inwardly with respect *to-one auotherf'they will adjust and maintain "the ,pin rails'in amen vrightangle relation.

By tightening up the clamps 34;, no slippingior sliding of thebutt ended rails *will be permitted during the final adjustment-of the corner c'lamp'syso that the tightening ef the latter will'square up "the frame, and, at "the same time, these corners, and "the diagonal positioning of the} clamps *will efiect a firm bracing for reinforcement of the frame" as 'a whole "and "afiord a'mnc'h'more rigid-union o'fthe rts 'thanifth'e 'rails were ai'so bntt en d in thilg side. h f

i romt e ore i it wil be'a arent that the "frame ig zi virhole compris t "rails which 'are but't' connected upon'frme side and overlapped .and .dia (man "braced onfthe other sidefandthat' enon'uhction and co- H h'ods 'ofsecuremen't results 111 "a union e f the component parts of the frame which possesses 98 advantages both by reason of the inherent the overlapped relation of U entered through rigidity of the union afforded by the brace clamps, and by reason of the squaring up effect which such clamps afford during the assembling of the frame.

I claim:

1. In a device of the class described, the combination of four rails arranged in the form of an open frame, the rails at two of the corners being assembled in flush relation to one another and the rails at the other two corners being arranged in overlapped relation to one another, means for engaging the flush corners, diagonally disposed brace clamps embracing provided with oppositely facing abutting members adapted to engage diagonally opposed angles at such corners, and means for adjusting said opposed abutments relatively to one another to engage and hold said corners, each of said opposed abutments being provided with contact faces in oppositely converging relation to one another and lying in right angle relation to one another to square up said corners, substantially as described.

2. In a device of the class described, the combination of four rails arranged in the form of an open frame, the rails at two of the corners being assembled in flush relation to one another and the rails at the other two corners being arranged in overlapped relation to one another, means for engaging the flush corners, diagonally disposed brace clamps embracing the overlapped corners provided with abutting members adapted to diagonally opposed angles at such means for adjusting said opposed abutments relatively to one another to engage and hold said corners, each of said opposed a-butments comprising right angularly disposed contact faces adapted to square the frame and connecting end walls, and an adjusting screw carried by a fixed portion of each clamp and bearing against the proximate abutment, substantially as described.

3. In a device of the class described, a brace clamp engage corners,

comprising in combination spaced side plates and a connecting cross head at one end thereof, an adjusting screw the cross head, and a pair the overlapped corners of abutments having inwardly oppositely facing angularly disposed contact faces in oppositely conver ing relation to one another, one of the a utments being fixedly secured between the side plates, and the other abutment being slidable between said plates and being engaged by said adjusting screw,

substantially as described.

4. In a device of the class described, a cor.- ner brace clamp comprising in combination a pair ofside plates connected at one end by a cross head and each provided at a point adjacent thereto with an elongated slot, the edges of the cross head being turned inwardly to afford reinforcing flanges, an adjustable abutment embraced between the side plates of the clamp near of and being formed to provide inwardly facing contact faces at right angles to one another and being provided with end walls in close contact with the inner walls of the side plates, said end walls having outwardly projecting tongues slidably engaging said the head end therea slots, an adjusting screw entered through the a pair of side plates connected atone end by a cross head and each provided at a point adjacent thereto with an elongated slot, an adjustable abutment embraced between the side plates of the clamp of and being formed to provide inwardly facing contact faces at right angles to one another and being provided with end walls in close contact with the inner walls of the side plates, said end walls having outwardly projecting tongues slidably engaging sai slots, an adjusting screw entered through'the head and bearing against saidadjustable abutment, and a slmilarly disposed abutment at the far end of the clamp rigidly secured between the side plates thereof, substantially as described.

near the head end 'thereformed oppositely 

